Self-aligning idler roller for belt conveyers



NOW. 25, 1952 Q RAWLINSON 2,619,223

SELF-ALIGNING IDLER ROLLER FOR BELT CONVEYERS Fil ed Sept. 6. 1949 sSheets-Sheet 1 INVENTOR. 0515 emu/Nam *9 54 56 3 BY F g,@ a $5421 NQV.25, 1952 o. RAWLINSON SELF-ALIGNING IDLER ROLLER FOR BELT CONVEIYERSFiled Sept. 6, 1949 3 Sheets-Sheet 2 N MM w w m f VM 7 W A f n a 0 Nam25,19 Q. RAWLINSON SEL F-ALIGNING IDLER ROLLER FOR BELT CONVEYERS FiledSept. 6. 1949 3 Sheets-Sheet 3 BEAT TEA VASL.

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Bmaentor 0l 1691446 l/VJON s w u. e U ul 0 t t a Patented Nov. 25, 1952SELF-ALIGNING IDLER ROLLER FOR BELT CONVEYERS Ocie Rawlinson,Birmingham, Ala.

Application September 6, 1949, Serial No. 114,242

3 Claims.

My present invention relates to self-aligning idler rollers forsupporting either the load carrying or return flight of a belt conveyor,and has for an object the provision of such apparatus which embodiessimple yet effective means for counteracting oif-center conditions ofthe belt without damage to the belt.

My invention contemplates a self-aligning roller or assembly of the samewhich is mounted in a suitable supporting frame work in turn pivotallymounted for movement diagonally of the center line of the belt, togetherwith auxiliary rollers at the ends of the belt supporting roller orrollers, said auxiliary rollers having greater rolling friction than thesupporting rollers, whereby when the belt runs to one side it engagesthe auxiliary rollers, pivoting the whole assembly diagonally of thecenter line of the belt, thereby re-centering the belt.

A further object is to provide apparatus of the character designated inwhich the increased friction of the auxiliary rollers is provided bymeans of bearings larger in diameter than the bearings in the main beltsupporting roller, thus assuring smooth and trouble free operation, andeliminating damage to the edges of the belt as has been the case in someprior art apparatus.

A further object is to associate with one or more such pivoted rollerassemblies a spring actuated mechanism operable to bias the assembliesto centered position after the belt runs off the auxiliary rollers inmoving back to re-centered position, thus eliminating possibleundesirable oscillations of the assembly about its pivot point.

A still further object is to provide the auxiliary rollers in the mannerset forth which on several adjacent sets of supporting rollers increasepro gressively in axial length in the direction of travel of the belt,thus to compound the centering effect of the auxiliary rollers, and toconnect the pivoted assemblies together by links, causing a plurality ofthe same to act in unision in recentering the belt.

Apparatus illustrating the features of my invention is shown in theaccompanying drawings forming a part of this application in which:

Fig. 1 is a plan view, partly broken away and in section, showing agroup of my improved idler roller assemblies which may be used eitherfor the return flight of the belt or as a non-troughing support for theload carrying flight thereof;

Fig. 2 is a fragmental plan view of a set of the rollers, partly brokenaway and in section to illustrate the bearings of the main and auxiliaryrollers;

Fig. 3 is a detail sectional view taken generally along line III-III ofFig. 1;

Fig. 4 is a detail sectional view taken generally along line IV-IV ofFig. 1;

Fig. 5 is an end elevational view of one of the roll stands shown inFig. 1;

Figs. 6 and '7 are somewhat diagrammatic views illustrating thefunctioning of my improved spring biased mechanism for urging thepivoted roll supporting assemblies to center position; and,

Fig. 8 is a transverse sectional view of a belt conveyor equipped withmy improved apparatus, certain parts being broken away for the sake ofclarity.

Referring now to the drawings for a better understanding of myinvention, and more particularly to Figs. 1 to 5 inclusive, I show aseries of belt supporting units indicated generally by the letters A, B,and C. The units A, B and C are spaced apart along the belt in themanner well understood, to support the flights of the belt at intervals.In the case illustrated the flight preferably supported by rollers ofthe type shown in Fig. 1 is the return or non-load carrying flight,although the same may be used to support the loaded flight. The outeredges of the belt are indicated at l0 and H in Fig. 1, and the belt isassumed to be moving in the direction of the arrow l2. Except as will benoted each of the units A, B and C are identical, and hence adescription of one will sufiice for all.

Each of the units A, B and C may comprise a stationary support [3 in theform of an inverted channel. At the longitudinal mid-point of thechannel I3 is a boss l4.

Mounted to pivot diagonally of the centerline of the belt is a rollersupporting frame It. Adjacent its longitudinal mid-point the frame It isprovided with a boss I1, adapted to fit with its face flush against theboss 14. A pin 18 secures the two bosses against displacement other thanrelative pivotal movement. The member I 6 preferably is in the form ofan inverted angle for reasons of strength, and its boss I! is secured bywelding the same to the underside of a plate [9, in turn welded to themember l6.

On each end of the swingable frame It I provide upstanding brackets 2|.A cross shaft, indicated generally by the numeral 22, extendscontinuously across the frame [-6 and has its ends secured to theupstanding brackets 2| by means of U-bolts 23. The member I6, endbrackets 21 and shaft 22 thus are free to pivot about the pin l8 in adirection diagonal to the center line of the moving belt. 7

As best shown in Fig. 2 the outer end of the shaft 22 is reduced andthreaded as indicated at 24. Surrounding the reduced end 24 is a sleeve25. Pressed on the outer end of the sleeve 26 is an adapter 21 having athreaded section 28 adjacent its outer end. Pressed onto the adapter isthe inner race 29 of a ball bearing 36, the inner race being heldagainst the shoulder 3| by means of a nut 32 screwed onto the threadedsection 28 of the adapter.

Disposed to rotate about the adapter 2'! is a relatively short auxiliaryroller 33 in the form of a length of tubing or a casting of the shapeshown. Adjacent its outer end is a threaded section 34 and adjacent itsinner end is a shoulder 36 against which the outer race 3.! of thebearing 30 is adapted to be pressed. Grease seals 39 and 4| may beprovided to retain grease in the bearing in the manner understood. Thesleeve 26 as well as the adapter 21 pressed thereon are held in place onthe end of the shaft 22 by means of a nut 42.

The main belt supporting roller 63 comprises a cylindrical casting orlength of tube having an internally threaded section 44 at each end.Pressed into each end of the roller 43 is an adapter 46, the inner endsof the adapter being connected by means of a grease tube '1. The roller43 is supported for rotation on a bearing 48, the inner race 49 thereofbeing pressed onto the sleeve 25, and abutting the shoulder 5| formed asa result of reducing the outer end. 24 of the shaft 22. The outer race52 of the bearing 48 may be pressed into the adapter 46, and the partsare held assembled by means of a nut 53. A suitable packing 54 may beused to retain grease within the grease tube 41 and around the bearings48 at the ends of the roller 43.

As shown in Fig. 2, the effective diameter of the bearings 43 for themain roller 43 is considerably smaller than the effective diameter ofthe bearings 30 of the end or auxiliary rollers 33. It will at once beapparent that the result of this is to impart to the end rollers 33greater resistance to rotation than is possessed by the main beltsupporting rollers 43. It will be understood that each end of the roller43 is equipped with a bearing 48 and the associated adapter and nut, andthat the roller 33 on the opposite end of the shaft 22 is identical withthe one shown in section in Fig. 2. For a reason later to appear I makethe roller 33 slightly larger in diameter than the roller 43, and bevelthe inner edge thereof as indicated at 56.

From the mechanism already described the principal features of myinvention may now be readily explained and understood. Considering Fig.1, and assuming that there is but one of the units present, say forinstance the unit C, the operation of the device is as follows: With thebelt moving in the direction of the arrow I2 and centered with respectto the main supporting roller 43 of the unit C, the edges of the beltoccupy the positions indicated by the dotted lines I0 and H. However,let it be assumed that for some reason the belt becomes uncentered, theedges and l l moving to the positions indicated by the dot-dash lines inFig. 1. Under these conditions the belt will have moved up onto theauxiliary roller 33 at the end of the-main roller toward which the belthas moved, engaging this roller, and causing rotation thereof. As willbe remembered, roller 33 has greater resistance to rotation than doesthe main roller 43. This resistance to rotation causes the entire rollgroup to pivot on the pin it in a direction to follow the movement ofthe belt, since the roller 33 on Which the belt is engaged tends tofollow the edge of the belt engaging the same. With the main rollerpivoted diagonally the belt moves back toward center position in themanner understood, moving off the roller 33 and wholly back onto themain roller 43. Should the belt become uncentered in the oppositedirection the roller 33 on the opposite end from that just describedcomes into play, causing its adjacent end of the swing frame to move inthe direction of travel of the belt, thereby causing the belt to againbecome centered.

It will be especially noted that no damage is done to the edge of thebelt, because the beveled edges 56 readily permit the belt to ride uponthe rollers 33. I make the rollers slightly larger in diameter than theroller 43 in order to accentuate the pivoting action about the pin 13when the belt first engages the roller In view of the fact that thebearings and rollers carried thereby are balanced, my improved apparatusis exceptionally free of vibration and uneven running, hence increasingmaterially the life of the supporting bearings and the belt.

Referring now to Figs. 1, 3, i, 6 and 7, I show my improved apparatushaving associated therewith an equalizing means which is particularlyuseful for belts which have an exaggerated tendency to becomeuncentered. In this instance I place the units A, B and C in normallyspaced, belt supporting relation and connect the together by means ofrigid tie rods 5? pivotally secured to each of the frame members it asat 58 to an ear 59 carried by the frame member. On one set of suchconnected rollers, for instance the unit A, I place a spring biasedmecha nism, later to be described in detail, and which is effective tobias the sets A, B and C toward position normal to the center line ofthe belt.

As best shown in Fig. l I provide beneath the swing frame member 16 ofthe unit A a plate 6|. Also welded beneath the swing frame member IE, ata point further toward the thereof from the pivot point IS a secondplate 62. Fixed to the stationary member i3 is a plate 53 extendingtransversely of the swing frame It. Each end of the plate 62 is providedwith lapped overhanging plates 62a forming in effect a yoke on the endsof the plate 62.

To each projecting end of the cross plate 6| I secure one of the clevisends 64 of a turn buckle 66. To the opposite clevis end B? of each turnbuckle 68 I pivotally mount by means of a pin 68 one end of an arm 69.The outer projecting ends of the plates 62a are slotted as indicated atH. I secure to the arms 69 pins 72 which are disposed to fit slidably inthe slots H. The outer ends of the arms are cross connected by a tensionspring 13.

Pivotally mounted on the pins M to the projecting ends of the plate 6-3are a pair of levers IS. The inner ends of the levers '56 are rounded asindicated at El and are turned outwardly with respect to thelongitudinal center line of the member [6, thus to engage against theinner edges of the respective arms 59. The ends of the cross plate 62contact the inner edges of the arms 78 when the pivotally mounted rollsupporting frame is normal to the longitudinal center line of the belt.

As shown clearly in Fig. 1, when using the centering mechanism andconnecting links 5?, I preferably make the rollers 43 progressivelylonger in the direction of travel of the belt, and

the rollers 33 progressively shorter in the direction of travel of thebelt. Thus, the roller 43 of unit A is substantially equal in length tothe Width of the belt, while rollers 43 of units B and C are slightlyand progressively longer than the width of the belt. Similarly, therollers 33 of unit A are slightly longer than those of unit B, and thoseof unit B are slightly longer than those of unit C. The reason for thisconstruc tion will appear as the operation is described.

Referring now particularly to Figs 6 and 7 I indicate somewhatdiagrammatically the functioning of the centering apparatus. Let it beassumed that the belt is centered on the roller 43 of each of the unitsA, B and C and is traveling in the direction of arrow I2. Under theseconditions the spring I3 biases the longitudinal axis of the swingframes I6 to a position normal to the center line of the belt. The forceof the spring is exerted through the arms 69, to pivot points 68consequently the bottoms of the slots II. The rounded ends I! of thearms 16 engage the inner edges of the arms 69, while their inner edgesengage the ends of the plates 32, these parts being made so that thereis very little pivotal movement of the arms I6 when the belt is centeredLet it now be assumed that the belt moves so that its edges I0 and I Ioccupy the positions shown by the dot-dash lines in Fig. 1. In thisposition the several frames I6 carrying the rollers 43 and 33 will eachpivot to the position shown in Fig. 6. This causes the inner ends of thearms I6 to move to the right as indicated, and causes the rounded end IIof the right hand arm I6 as viewed in Fig. 6 to engage the inner edge ofthe arm 69, moving its corresponding pin l2 out of the bottom of theslot II in the associated plates 62a. The spring 13 thus tends to returnthe swing frames IE to the left back to centered position due to thedifference of the leverage exterted between the points 68 and II on theright hand side, Fig. 6, as compared to the force exerted by the springin pulling the left hand arm 69 to the right. This difference in favorof leftward movement will be understood by considering that therightward force is less because the effective moment arm of the arm onthe left hand side is the distance between its pivot point 68 and itspin I2. The swing frame thus is biased left- Ward to centered positionfrom the position shown in Fig. 6, and when the same reaches thisposition it does not tend to override to the left as would be the casewere the centering mechanism not used. Further, this system of linkageis superior to the use of two springs secured to the ends of the swingframe I6 for the reason that no balancing of the springs is necessary,the single spring 13 being used to pull the swing frames in bothdirections.

Referring to Fig. 7, it has been assumed in this position that the belthas become uncentered in the direction opposite that shown in Figs. 1and 6. From an inspection of this figure it will be seen that the partsassume a position opposite to that in Fig. 6 wherein the spring I3 tendsto move the swing frames I6 to the right, back to centered position.

By the use of the centering mechanismshown and the rigid rods or links51, together with the main and auxiliary rollers of different lengths asshown, I am enabled to compound the offcentering forces of the belt inorder to bring the same back to centered position, and to accomplishthis with one centering mechanism.

By an inspection of Fig. 1 it will be seen that when the belt firstcommences to get off-center it contacts the roller 33 of unit A beforeit contacts the roller 33 of unit B. Likewise, because the rollers 33 ofunit C are in turn shorter than those of unit B the belt contacts theroller 33 of unit B before it contacts the roller 33 of unit C. With theunits hooked together by the links 51 the difference in length of therollers 33 causes the belt to commence its movement toward centeredposition at points along the length thereof removed from the actualoff-center point. Thus the overall centering effect is accentuated bymoving all of the units in unison since the belt in off-center conditionremains engaged for a greater length of time with the longer rollers 33than would be the case if they were of equal length.

Referring now to Fig. 8 of the drawing I show my improved mechanismassociated with both the load carrying flight I5 and return flight 15aof a conveyor belt. In this instance the load carrying flight is shownas supported on troughing rolls 18, 78a and 182), each of whichcorresponds to the main belt supporting roller 43. At the outer ends ofrollers 18 and 18b, I provide rollers 33a, similar to the roller 33.These rollers are supported on a swing frame IBa, having the boss I'Iaat the mid point and resting pivotally on the boss I la carried on thecross frame I3a. The frame I3a may be supported in elevated positionabove the return flight rollers on superposed channels I9 and BI,resting on channels 82 at the ends of the lower roller frame work. Inthe manner understood the adjacent ends of rollers Ilia-18 and I8a18bare supported on brackets 83. The outer ends of the shafts passingthrough the ends of the rollers are supported by U-bolts 23. The rollers330, are mounted for rotation on a shaft 22a and on bearings similar tothose shown in Fig. 2 for the auxiliary rollers 33. Likewise, therollers 18, 13a and 18b are provided with the bearings 48, and which aresmaller in diameter than the bearings supporting the rollers 33. Ifdesired, there may be associated with the upper rollers being describedthe centering mechanism such as is shown in Fig. 1 and consisting of theleverage system, and a plurality of frames lBa may be connected togetherby means of the lugs 59 and links 51.

The rolls and supporting framework therefor for supporting the flight15a of the belt are identical with the ones shown in Fig. 1, and nofurther description is deemed to be necessary.

From the foregoing it will be apparent that I have devised an improvedidler support for belt conveyors which is efiective to return anoff-centered belt to its correct position. In actual practice I havefound that my invention is extremely eifective for its intended purposeand that it is far superior to those types of centering mechanisms inwhich the edges of the belt in ofi-center position engage rollers, stopsor the like to swing the pivotally mounted framework. Further, myimproved device is balanced at all times since the bearings areconcentric, thus preventing vibration and excessive wear on the belt.

While I have shown the centering mechanism and links 5? for associationwith my improved apparatus it will be understood that this portion of myinvention is in addition to the principal feature thereof. The principalfeature consists of the main and auxiliary rollers in which theauxiliary rollers have greater resistance to rolling friction than dothe main rollers, and the whole being supported for pivotal movementdiagonally of the belt. The centering mechanism and links 51 for tying anumber of the units together for mutual centering movement is desirablefor use on belts which have an exaggerated tendency to run off-center.In practice I have found that the use of one of the units A, B or Calone, without the centering mechanism and links is sufficient in alarge number of cases to maintain a belt centered.

While I have shown my invention in but two forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications, without departing from thesipirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appended.claims.

What I claim is:

1. In apparatus for supporting a conveyor belt at intervals along alength thereof, a plurality of sets of belt supporting idler rollersspaced from each other along the belt, each of said sets embodying atleast one main belt supporting idler roller, the main roller of each setbeing progressively longer than the next rearward main roller whenconsidering the direction of travel of the belt, a frame for rotatablysupporting the main rollers of each set, means to mount the frames forpivotal movement diagonally of the longitudinal axis of the belt, and anauxiliary roller having greater resistance to rotation than the mainroller mounted on the frame adjacent the ends of said main roller and onopposite sides of 1e pivot point of said frame, the auxiliary rollers ofeach set being progressively shorter than the next adjacent rearwardroller when considering the direction of travel of the belt.

2. In apparatus for supporting a flight of conveyor belt, a main beltsupporting roller, a frame in which the roller is mounted for rotation,means supporting the frame adjacent its longitudinal mid-point andpermitting the same to pivot diagonally of the center line of the belt,an auxiliary belt supporting roller rotatably mounted on the frame ateither side of the pivot point thereof closely adjacent the ends of themain roller and having greater resistance to rotation than the mainroller, a cross member secured to the frame adjacent one end, a secondcross member secured to the frame at a point nearer the end than thefirst cross member, a pair of arms having their inner ends pivotallyconnected to the ends of the first cross member, there being slots inthe ends of the said second cross member, a pin on each arm slidable inthe slot of the adjacent end of the second cross member, a pair of linkspivotally mounted at their outer ends on fixed pivot points and with oneedge of the inner ends thereof disposed to bear against the inner edgesof the associated arm, a stop member on the ends of said second crossmember disposed to engage the edges of the links opposite the edgethereof adjacent the arms, and a tension spring connecting the outerends of the arms.

3. Apparatus as defined in claim 2 in which the inner ends of said linksengage the edges or" the arms at a point between the pivot pointsthereof and said pins.

OCIE RAWLINSON.

REFERENfiES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,192,128 Sibley July 25, 19162,012,089 Sayers Aug. 20, 1 35 2351,39 1- Klein Oct. 12, 1948 2,561,641Thomson July 24, 1951 FOREIGN PATENTS Number Country Date 28,756 GreatBritain Of 1910

